The name was similar to one revealed, after the death of the grandmother who raised Walker, as that of his real father. Walker researched the name on the Internet but didn't find anyone who fit the profile.

But Detective Clay Hamilton did. Following his hunch, Walker visited Hamilton's desk and casually asked questions. He found that Hamilton was 53, about the right age and - matching his mother's account - grew up in the Richmond area, hung out with people in Goochland County and dated a girl named Billie Joe.

Walker, 37, spoke to his mother that night and told her generally about Hamilton. She insisted his father's first name was Clayton, not Claiborne.

Walker then asked whether she knew a Billie Joe Walker.

"There was a pause on the phone, and she said, 'That's your dad,' " Walker said, referring to Hamilton.

Billie Joe was his mother's old nickname, coming from Bobbie Gentry's 1967 song "Ode to Billie Joe."

Walker called Hamilton and told him, "I think you're my father."

Results of a DNA test confirmed the two, who never met each other before working together, are father and son.

Hamilton said he had a brief romance with Walker's mother when he was 15. She was a few years older and separated from her husband at the time. Hamilton said he lost touch with her after she became pregnant, went back to her husband and moved. He said he tried to locate her and the baby he suspected was his son but was unsuccessful.

Despite the separation, Hamilton and Walker followed similar paths in life, including stints in the military and working for urban police departments despite growing up in the suburbs.

They have spent the last month getting to know each other's families: Walker's wife and 5-year-old son; and Hamilton's wife, 12-year-old son, 35-year-old daughter and granddaughter, 8. They plan to have a family get-together that will include Walker's mother.

"I feel like we've got a lot of time that we've missed," Hamilton said. "Of course, you can't ever make up for lost time. We're going to do what we can to make it up."